Relays are widely used as switching devices. For example, the telecommunications industry uses relays for many switching applications, at a current market value of approximately $500 million per year. Mechanical relays are highly developed commodity products. An example of a conventional mechanical relay is the NAIS TK Ultralow Profile 2 Amp Polarized Relay. Relays are often encapsulated with a high pressure gas. See U.S. Pat. No. 4,168,480 to De Lucia.
Microelectromechanical systems (MEMS) have recently been developed as alternatives for conventional electromechanical devices such as relays. MEMS devices are potentially low cost devices, due to the use of microelectronic fabrication techniques. New functionality may also be provided because MEMS devices can be much smaller than conventional electromechanical devices. A MEMS relay, also referred to herein as a micro-relay or a micromachined relay are described in publications entitled "An Electrostatically Actuated Micro-Relay" by Drake et al., The 8th International Conference on Solid-State Sensors and Actuators, and Eurosensors IX, Stockholm, Sweden, Jun. 25-29, 1995, pp. 380-383; "Thermally Controlled Magnetization Microrelay" to Hashimoto et al., The 8th International Conference on Solid-State Sensors and Actuators, and Eurosensors IX, Stockholm, Sweden, Jun. 25-29, 1995, pp. 361-364; "Electromagnetic Linear Actuators With Inductive Position Sensing for Micro Relay, Micro Valve and Precision Positioning Applications" by Guckel et al., The 8th International Conference on Solid-State Sensors and Actuators, and Eurosensors IX, Stockholm, Sweden, Jun. 25-29, 1995, pp. 324-327; "Electromagnetic Microrelays: Concepts and Fundamental Characteristics" by Hosaka et al., Sensors and Actuators A, Vol. 40, 1994, pp. 41-514 47; and "Rugged Design for Reliable Switching: Micro A Relay Sets New Automotive Standards" by Knuppel, Siemens Components (English Edition), Vol. 29, No. 4, July-August 1994, pp. 30-32, the disclosures of which are hereby incorporated herein by reference.
Micro-relays have heretofore made few inroads in the conventional mechanical relay market. The primary reasons for lack of market penetration appear to be cost and performance. As to cost, even though conventional relays may require coil winding and assembly operations, the mature market and off-shore assembly of conventional mechanical relays has maintained a low cost. As to performance, telecommunications relays typically must provide a high breakdown voltage of about 2000 volts or more, so as to withstand a direct lightning strike. A long lifetime and vibration resistance must also generally be provided. In view of the higher cost and lower performance of micro-relays, their market penetration presently continues to be small.